During an intercostal nerve block, the needle is inserted at the lower border of the rib to access the neurovascular bundle. What is the correct arrangement of structures in the costal groove from superior to inferior?

• A Artery (superior), vein (middle), nerve (inferior)
• B Nerve (superior), artery (middle), vein (inferior)
• C Artery (superior), nerve (middle), vein (inferior)
• D Vein (superior), artery (middle), nerve (inferior) — VAN from top to bottom ✓

Explanation

The costal groove on the inner surface of each rib lodges the intercostal neurovascular bundle in the order: vein (superior), artery (middle), nerve (inferior) — remembered by the mnemonic VAN (Vein-Artery-Nerve) from superior to inferior. For intercostal nerve block, the needle is inserted at the inferior border of the rib to avoid the artery and vein above the nerve, reducing risk of vascular injury. For diagnostic and therapeutic chest needle procedures (thoracocentesis), the needle is introduced just above the upper border of the lower rib.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.